Microscope

ABSTRACT

A microscope is disclosed for observing a magnified area. Fade-in means ( 32   a ) arranged in the path ( 1 ) of the rays of the microscope ( 82 ) reflect a thin focused beam of light ( 101 ) into the path ( 1 ) of rays. The beam of light ( 101 ) is deflected or modulated by deflecting means ( 102 ) to supply an image that can be recognised by an observer ( 100 ). The image may be projected onto the object ( 22 ) either directly or indirectly, for example through a diffusing screen ( 108   a ).

[0001] The invention relates to a microscope having at least one beampath and an optical system along an optical axis, and having a fade-inelement for reflecting in image information for an observer's eye.Microscopes in the sense of the invention are to be understoodprincipally, but not exclusively, as devices which have a mainobjective, a tube and an eyepiece for looking into. In the widestunderstanding of the invention, therefore, all other opticallymagnifying devices are to be understood which are directed onto anobject to be magnified and make visible to the observer's eye amagnified image of the object observed. Microscopes, in particularstereomicroscopes, for example surgical microscopes, in particular alsovideo (stereo) microscopes which are connected to an electronic dataprocessing unit and/or a display are comfortable for a user when thelatter is not exclusively dependent on the image currently seen throughthe main objective of the microscope, but also obtains when looking intothe tube of the microscope additional information which is generallysuperimposed on the currently seen image. This can be graphiccharacters, symbolic representations, marks, but also superimposedimages of the same object which are obtained, for example, with the aidof image processing software from the currently seen object or by meansof other visualizing measures (for example X-ray pictures, CT etc.) fromthe same object.

[0002] Microscopes with fade-in possibilities or image superimpositionpossibilities are also used, inter alia, in technology, for examplematerials engineering, material analysis, silicon technology,criminology, etc., but also, in particular, in medicine for diagnosis,serological examinations, during operations etc.

[0003] Chiefly in the case of surgical microscopes and, in particular,during an operation, a quantity of information arises which can be ofgreat importance to the surgeon. This is, for example, information onthe patient or his state of health or patient parameters such as pulse,blood pressure, oxygen content of the blood etc. These are in additionto the currently observed superimposing images, for example, informationon specific parameters of the microscope, information on the position ofthe observed operation zone, as well as control data which, for example,the surgeon delivers at will via control elements such as computer mouseor foot switch to the data processing device or to control elements forthe microscope, in order to control the latter as required, for exampleto focus it, etc.

[0004] The use of the invention in the field of surgical microscopy willbe taken up below by way of example. However, its application in theremaining fields likewise comes under the scope of protection of thepatent claims.

[0005] Surgical microscopes are used by the operating surgeon foroptical magnification of the operation zone. Operation technology is sofar advanced in this connection that magnifications in the region of 50fold and above are no rarity. It is important during an operation thatthe all important information is transmitted to the operating surgeon asquickly and unambiguously as possible, in order for him to be able toconclude the operation in as short a time as possible. Since theoperating surgeon preferably removes his eyes as little as possible fromthe eyepiece of the surgical microscope, and, conversely, difficultiesof comprehension can be expected with the spoken word, it is obvious forimportant information such as, for example, patient data, micoscopecontrol data or positional data to be rendered visible in the tube.

[0006] This is achieved according to known techniques by representingthe relevant information on a display and reflecting the image of thisdisplay into the tube via a beam splitter. Because the user always wantsa good light yield for the object observed, which can frequently beensured by high illumination densities at the object, the problem ofadequate optical density of the image reflected in or superimposed oftenarises in the case of reflecting in. In this case, tube displays (CRT)frequently provide no way out. The use of LCDs with strong backgroundilluminations is attended by disadvantages in the field of resolutionand also in attempting to reproduce thin lines, also since the pixelwidth of the LCDs is relatively large, and therefore relatively wideminimum line thicknesses are prescribed. Moreover, LCD pixels formrasters which can produce problems with edge definition and resolution.

[0007] If it is now desired, for example, to have edge improvements,image colorings, contrast improvements or other marks which are as thinas possible, and which have been prepared, for example, after priorrecording by means of video technology and by means of electronic imageprocessing, it can happen disadvantageously that the known possibilitiesproduce unsatisfactory performance with regard to brightness and/or linethickness. Contouring would be desirable, but not achievable optimallyusing the means of the prior art.

[0008] A special field for the superimposition of images rises, forexample, in the application of computer tomography (CT) or magneticresonance imaging (MRI) in conjunction with stereomicroscopy. Data areobtained from CT and MRI in order to obtain a sectional image of thezone of interest from the patient which, in the final analysis afterEDP, permits the representation on a computer monitor (stereo displayscreen) of a three-dimensional model which is faithful to reality. Byusing such three-dimensional images, the attending doctors are betterable to localize the type and spread of the diseased area. However, itis frequently the case that both the image currently seen and theavailable three-dimensional representation of X-ray or CT image data arenot clear enough for the relevant area to be identified during operationin a marked-off fashion with sufficient clarity from the remainingregion.

[0009] As already mentioned, contour reworking or contour representationsuffice for this identification to be performed optimally, but these areto be as bright and thin as possible in order not to cover otherdetails.

[0010] Accomplishing this is one of the main objects on which theinvention is based.

[0011] This object is achieved, for example, by applying the methodaccording to claim 10 and/or a device in accordance with claim 1.

[0012] The problems described are eliminated by superimposing onto afirst image, seen through the main objective (8) of a microscope, atleast one second image from a thin, focused light beam, in particular alaser beam which is deflected and/or modulated in a deflecting deviceand reflected into the beam path of the microscope via a fade-in elementin such a way that it visibly represents the second image for anobserver's eye. A thin light beam, in particular a laser beam, can begenerated in a virtually arbitrarily thin and bright fashion.

[0013] It is relatively easy for the components newly required for thisin accordance with claim 1 to be integrated into a microscope. Fade-inelements, suitable light sources, in particular lasers, are known per seto the person skilled in the art. However, despite their favorableproperties, they have evidently not been used so far for the effectsbeing sought in the field of microscopy.

[0014] It is not important here for the purpose of the invention whetherthe thin light beam or laser beam is projected by the optical systemdirectly onto the retina or onto an interposed diffusing screen, or elsedirectly in the other direction onto the object itself, in order torepresent the corresponding marking there on the object surface.

[0015] Within the scope of the invention, there are both variants inwhich, in the operating state, the light beam extends in the region ofan intermediate image plane of the optical system in a fashionapproximately parallel to the optical axis in the direction of theeyepiece, and variants in which a diffusing screen on which the lightbeam can be scattered is arranged in the intermediate image plane.

[0016] For the purpose of the invention, a diffusing screen is in thiscase any optical element on which a thin light beam is scattered uponimpingement in such a way that its point of contact can be seen fromdifferent points of view. Thus, this could also be an uncoated glassplate. However, it can also be, for example, a beam splitter to which ascattering coating is applied to a surface inside the optical system, orone surface of which is roughened.

[0017] According to the invention, any desired pictorial information canbe fed to the observer by means of a light beam and deflecting device.In accordance with a specific embodiment of the invention, thedeflecting device and/or the light source is controlled by an imageprocessing device for contour representation, which is coupled to animage recording device which is coupled to the optical system via afurther fade-in element. This permits direct feedback between the imageof the object which is seen and the image represented by means of thebeam. This variant is advantageous by virtue of the brightness of afocused light beam. Despite a bright operating field of view, the areato be emphasized is seen by the operating surgeon in a clearlyhighlighted fashion. This is so, of course, even in the case of variantsin which not only the image seen optically is the basis for the imagerepresentation of the beam, but also the diagnostic data, acting asthough at the same object position, from a diagnostic data device (forexample a CT, MRI, PE device or the like).

[0018] In the latter variants, it is preferred to provide in each caseat least one beam path per observer's eye (stereomicroscope), it beingthe case that in each beam path in each case one left-hand andright-hand item of partial image information, which are offset in termsof perspective in relation to the respective other one can be reflectedin from one, or in each case one deflecting device via a fade-in elementin each case, the deflecting device(s) being controlled by an imagerecognition and/or image processing device.

[0019] An image recognition device is to be understood as a system whichis able to recognize the identity of the objects observed throughdifferent observation units, and in this way enables image data to besuperimposed in the correct position. For this purpose, reference ismade expressly to Swiss Patent Application CH3932/94-0 (our ref.:R-P-3141-CH) of the applicant, in which a particularly suitable deviceis described in which image data can be corrected not only for correctposition but also optically and be superimposed in a fashion matched toone another. A combination of the two inventions is advantageous.

[0020] The preferred method is yielded in this connection when thedeflecting device is controlled by image information obtained from theobject observed through the microscope, so that, for example, contoursof object details are retraced, or object details are represented bymeans of grid lines or the like at the actual site of the object detailin the visual field area. Of course, such grid lines have the idealeffect principally in the case of stereomicroscopes when they are usedto retrace a specific object detail (for example a tumor) in threedimensions or in plastic terms.

[0021] In accordance with a development of the invention, a continuouslycontrollable light valve is placed in front of the light source, so thata user can regulate the brightness of the image faded in by means of thebeam. When conventional lamps are used, it is also possible, of course,for their brightness to be regulated via the power supply. In the caseof lasers, in particular, however, the abovementioned variant is to berecommended.

[0022] Operating convenience is enhanced if the light color of the lightsource or of the laser can also be adjusted, something which is possibleby measures known to experts in light sources or lasers.

[0023] Further advantages follow in accordance with further specialembodiments of the invention in which the image observed (backgroundimage) exerts a reaction on the superimposed image. According to theinvention, the procedure here is based on two points of view: relativebrightness of individual pixels with respect to one another, and totalbrightness of the image, limited by possible adaptation behavior.

[0024] Swiss Patent Application CH1091/94-3 (our ref.: R-P-3174-CH)describes an arrangement which permits super-impositions and dataadaptations mentioned above to be enabled as quickly as possible or inreal time. A combination of the present teaching with the teaching ofthe abovementioned application therefore provides further advantages. Tothis extent, the content of the abovementioned patent application isconsidered as being within the scope of the present disclosure.

[0025] Further details and embodiments of the invention as well asvariants thereof follow from the drawing. Of the figures representedthere, by way of example:

[0026]FIG. 1 shows a design principle of a microscope according to theinvention, without diffusing screen;

[0027]FIG. 2 shows a variant of FIG. 1 with diffusing screen and asystem for reflecting in patient data;

[0028]FIG. 3 shows a variant with a system for reflecting in and outadditional image data and feedback therebetween;

[0029]FIG. 4 shows a stereomicroscope with 3-D image super-imposition,and

[0030]FIG. 5 shows a design with a small movable mirror in the beampath.

[0031] The figures are described together and inclusively. The samereference symbols denote identical components. The same referencesymbols with different indices denote similar or functionally similarcomponents. The invention is not restricted to the exemplary embodimentsrepresented. Further arbitrary variants can be represented incombination chiefly with the teachings of Swiss Patent ApplicationsCH949/94-2 (our ref.: R-P-3112-CH), CH1525/94-0 (our ref.: R-P-3138-CH),CH1295/94-8 (our ref.: R-P-3139-CH), CH1088/94-3 (our ref.:R-P-3140-CH), CH1089/94-5 (our ref.: R-P-3142-CH), CH1090/94-1 (ourref.: R-P-3165-CH), CH1091/94-3 (our ref.: R-P-3174-CH), CH1092/94-5(our ref.: R-P-3175-CH), chiefly also CH3932/94-0 (our ref.:R-P-3141-CH). For the purpose of combining their teachings, all theseapplications fall under the disclosed content of this application. Theattached list of reference symbols is consequently continued here.

[0032] One the principles of the invention is illustrated in FIG. 1:

[0033] A beam path 1 having a magnifying optical system 33, of whichonly two lenses, specifically a main objective 8 and an eyepiece 18, arerepresented symbolically, has an obliquely positioned beam splitter 32 aby means of which both the image information is directed to the eyepiece18 through the main objective 8, and image information reflected in fromthe side is directed to the eyepiece 18. The beam splitter can be asemireflecting mirror or the like. It can also possibly be constructedin a miniaturized fashion as a small mirror which is bonded on a glassplate perpendicular to the optical axis 7, as is represented in SwissPatent Application CH1092/94-5 (our ref.: R-P-3175-CH), such a latterdesign always functioning with divergence of the beams 101, which, ifappropriate, requires additional computational outlay for the beamdeflection. According to the invention, the image information reflectedin from the side comprises an image of a thin, focused light beam 101,in particular a laser beam, which follows the lines to be representedpictorially in a repeated fashion at the required speed, thus renderinga coherent image, for example lines, numbers, letters, symbols, areasetc., visible to an observer. These are scattered on diffusing screen108 a and are distinguished there by a good brightness (virtuallyunlimited, depending on the laser power) and thus by a distinct contrastwith respect to the image seen through the main objective 8. The imageof the scattered laser beam is projected onto an intermediate imageplane 103 of the tube by means of a lens 31 via the beam-splittingmirror 32 a. The beam is deflected or moved by a deflecting device 102,known per se which has mirrors or the like which can move under control,and in this way can deflect a beam 101 irradiated into it. It goeswithout saying that a plurality of beams with, if appropriate, aplurality of deflecting devices as well, could also be providedsimultaneously. It is also conceivable, if required, for a plurality oflaser beams to be run together on the diffusing surface, in order toincrease the energy density and thus the brightness. The movement of thebeam 101 is represented symbolically by a dashed arrow of rotation. Thebeam 101 is obtained from a light source 64, in particular from a laser,which could, of course, also be integrated into the deflecting device.

[0034] Also represented in the exemplary embodiment shown is a lightvalve 107 which makes the brightness of the beam 101 controllable. Thedeflecting device 102, light valve 107 and light source 64 canpreferably be controlled arbitrarily from outside, in order for theimage to be represented by the beam 101 to be configured optimally interms of beam quality for the observer, whose eye 100 is represented.

[0035] In the exemplary embodiments in accordance with FIG. 1 and FIG.3, the beam 101 is deflected in such a way that, via the eyepiece 18, itprojects the image it produces directly into the observer's eye 100 oronto the retina thereof. The light source 64 used can thus be relativelyweak optically. In the region of an intermediate image plane 103 of theoptical system 33, the beams 101 are thus preferably parallel to theoptical axis 7 of the optical system 33. However, it is not essentialfor the beam 101 to be faded in at the point shown. A variant is alsoconceivable in which the beam is directed into the observer's eye 100only after the eyepiece 18. This variant is expedient particularly incombination with the teaching of Swiss Patent Application CH1092/94-5(our ref.: R-P-3175-CH), since it does not unnecessarily increase therequired distance of the eye from the eyepiece.

[0036] The object observed is represented symbolically with 22, thepurpose of this design being, for example, to draw a high-contrast,bright line around an object detail 22 a. The scope of the inventiontherefore also covers that variant in which the beam 101 is projectednot directly into the observer's eye 100, but directly onto the object22, the beam splitter 32 a then having, of course, to act inversely.

[0037] The beam can be used to represent, for example, patientinformation data such as blood pressure, heart rate etc. in graphicform, as indicated in FIG. 2.

[0038] By contrast with the first variant, a laser beam 101 is directedthere straight into the eye, as indicated symbolically. The opticianknows the measures required to project the beam 101 correctly straightonto the retina. A diffusing screen can thereby be eliminated, and thebeam can apply a high brightness and level of contrast with thecorrespondingly lower amount of energy. The image prescribed by thedeflecting device 102 a is thus produced directly on the retina and issuperimposed precisely there on the image seen through the mainobjective 8. In this design, it is immaterial which angle the beams makewith the optical axis 7, to the extent that they impinge only at thedesired site on the retina. As an alternative to this design, it wouldbe possible to use in the intermediate image plane 103 a diffusinggrating at which only the wavelength region of the laser light isscattered, while the other light wavelength regions pass unimpeded, withthe result that despite the diffusing screen there is no appreciabledarkening of the image seen below the main objective 8.

[0039] In the example represented, blood pressure and heart rate arerepresented in the area of the object detail 22 a which is seen. Thispatient information is obtained by known measuring instruments and, ifappropriate, conditioned via a data conditioning unit 89 (compare SwissPatent Application CH 1091/94-3 (our ref.: R-P-3174-CH)) in such a waythat suitable control data can be fed to the deflecting device 102 a inorder to permit quick real-time operation.

[0040] The example represented in FIG. 3 concerns an image-processing(video) evaluation of an image seen through the main objective, forexample object detail 22 a through an image processing device 104 awhich is coupled to an image recording device 9 a (for example CCD). Theimage recording device 9 a is coupled to the beam path 1 via an imagingoptical system and via a beam splitter 32 b, with the result that theimage processing device 104 a recognizes the object detail 22 a beingobserved. Represented by dashes are the image recording device 9 b andimage processing device 104 b, which can be provided in addition to oras an alternative to 9 a and 104 a. In the variant drawn with full lines(9 a, 104 a), in addition to the image of the object detail 22 a, theimage processing device 104 a also has available the image from thedeflecting device 102 b which is projected inversely by the device 104a. Subsequent correction is therefore easily possible. The presentexample is concerned with detecting contours on the object detail 22 aand enhancing them by means of beam superimposition (101). This makes iteasier for an operating surgeon, for example, to make out the areasinvolved more quickly and more clearly.

[0041] The beam splitter 32 a is arranged in this example approximatelycentrally about an intermediate image plane 103, and is itself providedwith a surface 108 b which scatters to a slight extent, with the resultthat an additional diffusing screen is eliminated.

[0042] In the exemplary stereomicroscope in accordance with FIG. 4,diffusing screens 108 a are again provided, on which partial imagesoffset by the parallax are represented per beam path 1 a, 1 b relativeto the respective optical axis 7 a, b; said partial images are combinedin the observer's brain to form a 3-D image. The deflecting devices 102c, d are driven for this purpose by an image recognition device 105,possibly with an image processing device 104, which receives its imageinformation—possibly via a data conditioning unit (89) (not represented)and/or via an image memory—from a 3-D image data recording unit ordiagnostic data device 106. The latter preferably operate not in thevisible wavelength region as do the microscope beam paths, but by meansof X-rays, alternating magnetic fields, positron beams, ultrasound orthe like.

[0043] Thus, for example, it is possible using this design tosuperimpose three-dimensional grid lines calculated from theabovementioned patient data on an object detail 22 a which is seenthree-dimensionally or is to be seen theoretically [sic], with theresult that an operating surgeon again obtains an area of interest tohim in a clear and bright fashion and highlighted with thin lines.

[0044] Of course, arbitrary combinations of superimposed images are alsocontained within the scope of the invention, such as alphanumeric data,contour enhancement and encirclements of areas.

[0045] The variant in accordance with FIG. 5 operates with a micromirrordeflecting unit having a drive in the tube 33, which directs a laserbeam 101 in the correct position against the observer's eye 100.

[0046] Not shown in more detail, but familiar to the person skilled inthe art as being within the scope of the invention are variants withcolored lasers or with electron beams which cause suitable fluorescentscreens or the like to light up with patterns. Such designs alsocomprise, if appropriate, vector display screens, where lines arefrequently retraced in each case by the beam.

[0047] The invention also covers variants in which instead of being feddirectly to the eye the light beams are firstly led to the object beingobserved and scattered thereon.

List of Reference Symbols

[0048] This list of reference symbols also contains reference symbols ofFigures which are contained in the above-mentioned applications since,as mentioned, these count as also having been disclosed for combinationpurposes within the framework of this invention. This applies, inparticular, to the microscopes with special beam paths and beamsplitters, and to the devices for measuring the magnification and thedistance from the microscope to the object as well as to microscopes forstereotactic operations etc.

[0049]1 a, b First beam path

[0050]2 a, b Second beam path (first beam paths laid geometrically oneabove another)

[0051]3 Mechano-optical switching element

[0052]3 a, 3 b, 3 c Opaque and preferably silvered stop

[0053]3 d LCD shutter element

[0054]3 e Micromechanical leaf mirror design

[0055]3 f LCD exchangeable shutter element

[0056]4 Beam splitters

[0057]4 a, 4 b Beam splitters

[0058]4 c Beam splitter for cutting out the measuring beam

[0059]5 Screen

[0060]5 a Semicircular surface

[0061]5 b Residual surface of the screen 5

[0062]5 c Circular segment surfaces

[0063]5 d

[0064]6 Spindle for screen

[0065]7 Central axis

[0066]7 a, 7 b Central axis

[0067]8 Main objective

[0068]9 a Electronic image recording device

[0069]10 Display

[0070]10 a Display

[0071]11 a, b Mirror

[0072]12 a, b, c Adjusting device

[0073]13 Zoom

[0074]14 a, b Motor

[0075]15 Reciprocal drive

[0076]16 Supply lead

[0077]17 Light source

[0078]18 Eyepiece

[0079]19 Deflecting mirror

[0080]20 Push rod

[0081]21 Rigid mirror

[0082]22 Object

[0083]22 a Object detail

[0084]23 a, b, a′, b′, c, d Plane plate

[0085]24 Rotary actuator

[0086]25 Linkage

[0087]26

[0088]27

[0089]28

[0090]29

[0091]30 Leaf mirror of 3 e

[0092]31 Tube lens

[0093]32 Fade-in element

[0094]32 a Beam splitter

[0095]32 b Mirror

[0096]32 c Second fade-in element

[0097]33 Magnifying optics

[0098]34 Arrows

[0099]35 Further mirror

[0100]36 Actuator

[0101]37 Bar

[0102]38 a, b Deflecting mirrors

[0103]39 Retroprism

[0104]40 Balance weight

[0105]41 Backing plate a, b, c: prismatic with integrated mirror

[0106]42 Color filter

[0107]43 Interval switch

[0108]44 Microprocessor

[0109]45 Measuring array a

[0110]46 Reference array a

[0111]47 Module for image data transmission

[0112]48 Extraneous image data input

[0113]49 Positioning motor for zoom 13: a, b

[0114]50 Connecting lines a-g

[0115]51 Magnification display a, b, c

[0116]52 Cam disk

[0117]53 Coupling

[0118]53 a Between positioning motor 49 and zoom 13

[0119]53 b Between cam disk 52 and magnification-d [sic] display 51 b

[0120]54 Mechanical tap

[0121]55 a, b Pointers

[0122]56 Laser

[0123]57 Measuring beam a, b, c, c1

[0124]58 Reference beam

[0125]59 Arrows for displaceability of the fade-in element 32

[0126]60 Microscope beam path a-e

[0127]61 First deflecting element a

[0128]62 Focusing element a, b

[0129]63 Optical conductor end piece a, b

[0130]64 Light source a

[0131]65 Second deflecting element

[0132]66 Sensor

[0133]67 Distance range a

[0134]68 Connecting line

[0135]69 Distance measuring system

[0136]70 Connection

[0137]71 Magnification measuring unit

[0138]72 Position determining system a, b

[0139]73 Interferometer

[0140]74 Semireflecting mirror

[0141]75 Reflector

[0142]76 Detector

[0143]77 Electromechanical adjusting element

[0144]78 Interferometer control

[0145]79 Grating

[0146]80 Detector CCD

[0147]81 Stages

[0148]82 Microscope

[0149]83 Arrangement for measuring the magnification of the microscope

[0150]84 Arrangement for measuring the object/microscope distance

[0151]85 Position-measuring system for determining the absolute positionof the microscope in space, and also for the purpose of being able toreach a conclusion upon the position of the visual field at the objectfrom knowledge of the object/microscope distance

[0152]86 Toolbox for different user programs

[0153]87 Command control element (computer mouse)

[0154]88 Command control element for controlling the movement of themicroscope (for example foot switch)

[0155]89 Data conditioning unit

[0156]90 Computer (workstation)

[0157]91 Control switch for microscope

[0158]92 Electromechanical control unit for microscope (zoom, focus,etc.)

[0159]93 Object

[0160]94 Second device (for example MRI unit or CT unit)

[0161]95 Superimposing device

[0162]96 Joint on the stand

[0163]97 Adaptive control device

[0164]98 a, b Detection system

[0165]99 Memory

[0166]100 a, b Observer's eye

[0167]101 a, b, c Beams

[0168]102 a, b, c, d Deflecting device

[0169]103 a, b Intermediate image plane

[0170]104 Image processing device

[0171]105 Image recognition device

[0172]106 Diagnostic device

[0173]107 Light valve

[0174]108 a, b Diffusing screen

[0175]109 Test object

[0176]110 Coordinate system

[0177]111 Enhanced contour line

[0178]112 Micromirror deflecting unit

[0179] b Spacing of the measuring beams 57 a and 57 b

[0180] b′ Spacing of the measuring beams 57 a and 57 b at the measuringarray

[0181] d 1, 2 Stereobasis

1. Microscope (82) having at least one beam path (1) and an opticalsystem (33) along an optical axis (7), and having a fade-in element (32a) for reflecting in image information for an observer's eye (100),characterized in that the fade-in element (32 a) is assigned a lightsource (64), in particular a laser, for generating a thin, focused lightbeam (101) which can be faded into the beam path (1) in a modulated formin a fashion corresponding to the image information via the fade-inelement (32 a) by means of a deflecting device (102).
 2. Microscopeaccording to claim 1, characterized in that the light beam (101) isprojected—directly, if appropriate—in the direction of the user's eye(100).
 3. Microscope according to claim 1 or 2, characterized in that,in the operating state, the light beam (101) extends in the region of anintermediate image plane (103) of the optical system (33) in a fashionapproximately parallel to the optical axis (7) or in that a diffusingscreen (108), which is preferably arranged out side the beam path (1),is projected onto the intermediate image plane (103), the light beam(101) being able to be scattered on it.
 4. Microscope according to claim1, 2 or 3, characterized in that the deflecting device (102) and or[sic] the light source (64) is controlled by an image processing device(104) for contour representation, which is coupled to an image recordingdevice (9) which is coupled to the optical system (33) via a furtherfade-in element (32 b). Stereomicroscope, having in each case at leastone beam path (1 a, b) per observer's eye (100 a, b), according to oneof the preceding claims, characterized in that in each beam path (1 a,b) in each case one item of partial image information which is offset interms of perspective—left-hand or right-hand one in relation to therespective other one—can be reflected in from one, or in each case onedeflecting device (102) via a fade-in element (32 a) in each case, thedeflecting device(s) (32) being controlled by an image recognitionand/or image processing device (105, 104) which is preferably driven bya separate diagnostic data device (106) which acts, however, as thoughat the same object position (for example a CT device, MRI device, PEdevice or the like).
 6. Microscope according to one of the precedingclaims, characterized in that a continuously controllable light valve(107) is placed in front of the light source (64).
 7. Microscopeaccording to one of the preceding claims, characterized in that thelight color of the light source (64) or of the laser can be adjusted, orin that more than one laser light source having different light colorsare provided, each being assigned a deflecting unit.
 8. Microscopeaccording to one of the preceding claims, characterized in that, asdeflecting element, at least one micromirror arrangement is providedwhich is arranged directly in the tube.
 9. Surgical microscope having amicroscope according to one of the preceding claims.
 10. Method forsuperimposing onto a first image, seen through a main objective (8) of amicroscope (82), at least one second image, characterized in that athin, focused light beam (101) from a light source (64) is deflectedand/or modulated in a deflecting device (102) and reflected into thebeam path (1) of the microscope (82) via a fade-in element (32 a) insuch a way that it visibly represents the second image for an observer'seye (100) by virtue of the fact that the light beam (101) is projectedas far as the retina of the observer's eye (100) and/or a diffusingscreen (108) on which the light beam is scattered is projected into theregion of an intermediate image plane (103) of an optical system (33) ofthe microscope (82).
 11. Method according to claim 10, characterized inthat the deflecting device (102) is controlled by image informationobtained from the object (22) observed through the microscope (82), sothat, for example, contours of object details (22 a) are retraced, orobject details (22 a) are represented by means of grid lines or the likeat the actual site in the visual field area.
 12. Method according toclaim 11, characterized in that the image information is preferablyobtained in three dimensions from a diagnostic data device (106)independent of the microscope (for example an X-ray device, CT device,MRI device, PE device, ultrasonic device etc.), both the microscope (82)and the diagnostic data device (106) being assigned—preferably by meansof test measurement on a standardized test object (109)—to a commoncoordinate system (110), and the image data being tuned to one anotherby means of a correction unit, if appropriate, so that completeagreement is achieved in the object detail position.